Incremental force and moment coefficients for a parallel blade-vortex interaction

Renzoni, P.; Mayle, R. E.

doi:10.2514/3.10538

Cited by 12 publications

(8 citation statements)

References 16 publications

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“…This is followed by the secondary wave corresponding to the much slower traverse of the vortex fragment across the chord. The resulting overall aerodynamic coefficients reflected these findings and were consistent with numerical predictions [14,15].…”

Section: Interactional Aerodynamicssupporting

confidence: 75%

“…To this end experiments on both parallel and oblique BVIs (Fig. 3) on the main rotor were performed as early as 1969 [11,12] and more comprehensively in later years [13][14][15]. The first experiments were pioneering whilst the latter, with the availability of more capable instrumentation, were more able to aid identification of the dominant phenomena involved in the interactions.…”

Section: Interactional Aerodynamicsmentioning

confidence: 99%

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Helicopter tail rotor orthogonal blade vortex interaction

Coton

Marshall

Galbraith

et al. 2004

Progress in Aerospace Sciences

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The aerodynamic operating environment of the helicopter is particularly complex and, to some extent, dominated by the vortices trailed from the main and tail rotors. These vortices not only determine the form of the induced flow field but also interact with each other and with elements of the physical structure of the flight vehicle. Such interactions can have implications in terms of structural vibration, noise generation and flight performance. In this paper, the interaction of main rotor vortices with the helicopter tail rotor is considered and, in particular, the limiting case of the orthogonal interaction. The significance of the topic is introduced by highlighting the operational issues for helicopters arising from tail rotor interactions. The basic phenomenon is then described before experimental studies of the interaction are presented. Progress in numerical modelling is then considered and, finally, the prospects for future research in the area are discussed.

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Section: Interactional Aerodynamicssupporting

confidence: 75%

Section: Interactional Aerodynamicsmentioning

confidence: 99%

Helicopter tail rotor orthogonal blade vortex interaction

Coton

Marshall

Galbraith

et al. 2004

Progress in Aerospace Sciences

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“…The vortex was, however, generated by the sudden pitching of an upstream aerofoil and was considered nominally two-dimen- In an associated study at Rensselaer Polytechnic Institute, Straus' colleagues (Renzoni and Mayle 1991) modelled the blade-vortex interaction by convecting a discrete twodimensional vortex past a Joukowski aerofoil. The unsteady flows developed about the aerofoil resulted in the development of a free wake of discrete vortices shed from the aerofoil.…”

Section: Yjc=oo Zvtc=oomentioning

confidence: 99%

“…A similar method is employed in the more comprehensive work of Beddoes (1987Beddoes ( , 1989, in which the full threedimensional flow field about the rotor is simulated, and the constants in the unsteady lift calculations are tuned with semi-empirical adjustments to computational parameters. Renzoni and Mayle (1991) were also able to use an indicial approach to appraise the unsteady flow field in the vicinity of a two-dimensional blade-vortex interaction. This work was notable for the correlations the authors were able to make, effectively simplifying an extensive range of predictions into a few descriptive curves.…”

Section: Introductionmentioning

confidence: 99%

Results from a set of low speed blade-vortex interaction experiments

Homer

Saliveros

Kokkalis

et al. 1993

Experiments in Fluids

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The results of a Blade-Vortex Interaction (BVI) experiment are presented. The experiments were the second series to be carried out at Glasgow University (see Kokkalis and Galbraith 1986, 1987), and reflect improvement to the facility. These improvements have resulted in sufficient resolution to observe clear evidence of vortex passage and propagative disturbances caused by the BVI. Additionally the quality of the pressure data permitted a meaningful assessment of force and moment coefficients, and a clear correspondence between their detailed time histories was observed. The data obtained are also compared with the results of previous studies, and qualitative and quantitative similarities are discussed.

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“…The vortex has a fixed finite core in the simulation and it was found that the details of the vortex structure were important for matching results. Later, efforts [19][20][21] were made on modeling vortex distortion during BVI by using discrete vortices instead of a single vortex during close encounters. Lee and Smith 22 modeled the vortex core distortion in detail.…”

Section: Figure 2: Schematic Layout Of the Test Setup By Surendraiahmentioning

confidence: 99%

Experimental Study of Vortex Dynamics during Blade-Vortex Interactions

Peng

Gregory

2014

52nd Aerospace Sciences Meeting

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This paper describes the first-phase work of a comprehensive study on vortex dynamics during parallel blade-vortex interaction (BVI). Study of the vortex behavior sheds light on the fundamental interaction mechanism of BVI, and provides important validation data for computational investigations. Evidence has been found in previous studies that the vortex behavior during BVI varies with Reynolds number, but the effects are not clear. In the current study, the relation between Reynolds number and vortex behavior was investigated extensively. The influence of other factors on vortex behavior, such as vortex strength, is also discussed. A pneumatic vortex generation system has been built, which is capable of producing vortices with good repeatability in location, size and strength. The experiment is performed in a low speed wind tunnel usinga planar particle image velocimetry (PIV) technique to characterize the vortex and record BVI incidence. Results indicate that the vortex behavior during BVI strongly depends on the separation distance (h/c) between the vortex and the airfoil. A decrease in vortex strength during BVI is generally observed forh/c< 0.3. The PIV results also reveal the relation between Reynolds number and the vortex strength variation during the interaction. Nomenclature c = chord of the target airfoil h = separation distance between vortex and airfoil Q = second invariant of the divergence of velocity field Re = Reynolds number u = magnitude of velocity fluctuation in turbulence V x = local streamwise velocity V y = local lateral velocity V ∞ = freestream velocity x = coordinate in streamwise direction y = coordinate in lateral direction Γ = circulation Δα = pitching amplitude λ = length scale of the smallest eddy in the flow μ = viscosity ω = vorticity

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Incremental force and moment coefficients for a parallel blade-vortex interaction

Cited by 12 publications

References 16 publications

Helicopter tail rotor orthogonal blade vortex interaction

Helicopter tail rotor orthogonal blade vortex interaction

Results from a set of low speed blade-vortex interaction experiments

Experimental Study of Vortex Dynamics during Blade-Vortex Interactions

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